Q15 Enclosure Help

[appleyard 0]

Scott / Anyone

I had emailed Scott about this but I'll post here. Basically my questions is as below.

I would like to seek help on my Q15 enclosure. I had builded a 3.65 cu.ft @ 34hz for the Q15. My specs and measurement as follows:

Net Volume: 3.65 cubic feet

Tuning Frequency: 34 Hz

Port Width: 5.25 inches

Port Area: 86.625 Square Inches

Port Length: 47.5 inches

External Dimensions: 34 wide x 18 tall x 22.75 deep

Now, after installing and basically setting the amp crossover, subsonic filter and gains I found that the bass was muddy at times and lacked the lows. So I checked my amp setting even using scope just to make sure it does not clipped or distort. After listening to some song, it sounded a bit better, louder but lacked the lows and not clean. I crossed my LPF at 80hz and my HPF at 60hz.

I always depends on WinISD for building my enclosure but facing problems when trying to key in the Q specs. So I relied with http://www.subwoofertools.com/forum/ported...mp;Fs=&CE=0

for my designs.

My question is:

1) Does bigger port area makes the sub muddy?

2) Does my tuning freq. is too high?

3) Does my enclosure design is totally wrong?

I planned to build another enclosure for it. The max I can go is 34 wide x 18 tall x 22.75 deep and I would tuned it something like 30hz. Any idea on the port dimension (width, height and lenght) ?

Thanks

Wynold

[DosOne 0]

Hey I dont know much about the technical stuff but I do know i have 2 differently shaped ported boxes that are designed by Scott for my Q 15 and mine sounds amazing, and get low and got pretty loud (145) The specs are 30hz and 4cubes. So if you want i can shoot the plans your way if your intristed and if you could fit one of them. I might as well share em' w/ other Q owners and save Scott some time since we know that he is a busy man, and he works hard to make us happy

Wes

[NDMstang65 403]

As Wes said, might want to tune it lower.

Ps - Never use specs in a program like Winisd, just set your volume and your port area and calculate the length. Response graphs are worthless on a program like that.

Thanks!

[theothermike 0]

send one my way wes. badboy4life5544@aol.com, or my pm's. TY. plan on reconing larger =]

[appleyard 0]

Wes

I see you sig and we are using the same sub there. Shoot me with your plan at wynold@lycos.com

actually my initial plan is to tuned it to 30hz but after playing around with it I realised that my port is too long to fit into the box. After 1 week of trying I decided to increase tuning freq. to shorten port lenght. Might be not a good idea though.

thanks

Wynold

[johny24 0]

i never use win isd any more, i always got wrong port lengths compared to other proven online calculators, and compared to scott

[DosOne 0]

I sent everyone the plans, have fun

Wes

[jockin my styLez 0]

can you send me the plans..im interested in getting a 15" Q or BL

[appleyard 0]

If you are wondering the max box size I can go:

Net Volume: 3.65 cubic feet

Tuning Frequency: 34 Hz

Port Width: 5.25 inches

Port Area: 86.625 Square Inches

Port Length: 47.5 inches

External Dimensions: 34 wide x 18 tall x 22.75 deep

may look at this to get some idea

http://i161.photobucket.com/albums/t203/wynold/DSC01284.jpg

http://i161.photobucket.com/albums/t203/wynold/DSC01283.jpg

http://i161.photobucket.com/albums/t203/wynold/DSC01282.jpg

Seriously no extra space to go.

[Fi Car Audio 64]

With the current setup you are having your enclosure peak out around 45 Hz... which probably sits around where you car naturally wants to peak... and is rather pronounced in that region vs the bottom end.

With the same space, you can swap the port to a 3.5 X 16.5 that is about 28" long... this will tune you to 30Hz and open up the box to be about 5 cuft net. This will push the box peak down into the mid 30s and extend bottom end performance.

VERY tight fit as it is...

Thanks,

Scott

[appleyard 0]

Thanks Scott

I was thinking to redesign my box into a smaller ones as I found it a bit impractical on my current box. I plan to reduce box size but was wondering whether I should go lower than 30hz.

my questions would be:

1. If I were to opt for 28hz, would I have significant loss in the 45-65hz region? Sometimes I would play some trance song.

2. If I plan to go by box dimension of Wide 33 Deep 14 and Tall 20. What would the port dimension would be if I would go for 30hz. Sub will be firing rear instead of upwards. So my port dimension would be 3.5 wide X 18.5 tall and port lenght would be at 30hz??

Wes

Would love you use your design but its going to be 24 in tall. Even with my current box height of 22.75 in is already half of the backseat headrest.

thanks

Wynold

Edited May 18, 2007 by appleyard

[appleyard 0]

errmmm.....help?

[appleyard 0]

Can I assume that if I would go for 33 Deep 14 and Tall 20 port dimension would be 3 wide 12.5 tall and 28 long at 30hz?

Planning to do my box next week.

thanks

Wynold

[natlazaro 0]

Hey I dont know much about the technical stuff but I do know i have 2 differently shaped ported boxes that are designed by Scott for my Q 15 and mine sounds amazing, and get low and got pretty loud (145) The specs are 30hz and 4cubes. So if you want i can shoot the plans your way if your intristed and if you could fit one of them. I might as well share em' w/ other Q owners and save Scott some time since we know that he is a busy man, and he works hard to make us happy

Wes

please send me the plans for this, thank you nat_lazaro@yahoo.com

[SSSnake 0]

Your HP filter is set too high (60Hz). Crank it down some while listening to some music with lows. I would start at 40 Hz (only if the statement about your box being tuned to 45 hz is accurate). A passband of 40 to 80 Hz is still very narrow. 60 to 80 Hz is NOT going to work.

[mlstrass 1]

Your HP filter is set too high (60Hz). Crank it down some while listening to some music with lows. I would start at 40 Hz (only if the statement about your box being tuned to 45 hz is accurate). A passband of 40 to 80 Hz is still very narrow. 60 to 80 Hz is NOT going to work.

x2

If your box is tuned to 34Hz, why are you setting your HPF (assuming you're using it as a SSF) to 60Hz. No wonder you're getting no lows.

I built a 3.5^3 @32Hz box for the GF's car and it hits plenty low, so I don't think it's your box, it's your amp settings.

[appleyard 0]

HPF - 60hz for comps

LPF - 80hz for subs

Subsonic - 32hz

explain to me again about the sub producing lows?

[theabunai 3]

I believe you got too much port area.....

At 3.65 cuft the optimal port area is around 51 square ft....

may want to try and lessen the port area....

Also you filters look fine....

You could bring the SS filter down to 30hz if you wanted to....

I know my subs sounded horribly muddy at a higher volume until I set all my Bass EQ settings to zero and then brought my amp gains up to just below distortion at 3/4 deck volume... not only did it actually sound much LOUDER and cleaner but played much much lower.....

[appleyard 0]

Guess I should update on what I was doing last time and other details so everyone got a clearer pics at it:

1. I know port area is too big as 16.5 height X 5.25wide port is pretty much too big for a 15" not to mentioned more than 40' long. The reason is because I couldnt use WinISD (I know but lets just stop with the WinISD thinggy) and I used some programs which wont allow for more flexible box design. So with the dimension of the box I ended up with those port dimension. I had to increase tuning freq. to shorten the port. If I would opt for 30hz the port lenght will be more ridiculous.

2. I set my gains, subsonic, HPF and LFP using scope and test tones. So the issued of distorsion and clipping wont come into play.

3. I set my mids at 60hz HPF and 80-100hz at LPF for subs.

4. Scott emailed me stating that port lenght over 40' are not recommended as it will increase the resonant freq. of the box and he also state that the box has a peak in mid 40's hz.

5. With the same box dimension he recommended me to go for 3.5 X 16.5 X 28 @ 30hz.

6. I was thinking of setting filters at hz down (31hz) as recommended by Scott but afraid it would bottoming out at lower freq.

7. I plan to use smaller dimension of box Wide 33 Deep 14 and Tall 20 to save some space. So I would like to know about port dimension at 30hz.

err .... any help?

[theabunai 3]

actually appleyard

If you decrease the ports width from 5.25 width it will allow you to shorten the port length for a lower tuned frequency...

In your case if you went with a 4 port width and a height of 16.5 your port length for a box tuning of 32 hz would be around 35" long

Or i would do what scott recommends 30hz with a 3.5 width will give you only a 28" long port....

the smaller the width the shorter the length can be to achieve a lower tuning.. just don't go to small to where you encounter port noise...

Scott suggested the same thing i suggested dropping the SS filter to around 30hz.....

The SS filter has a really steep roll off so it is fairly safe to say set your SS filter a few freq. below tuning.... it's when the sub starts hitting notes WAY WAY below tuning that can be really bad (tuned box at 40hz then your sub playing a 20 hz note...)

for the port dimensions for the last box you have (33w x 14D x 20H assuming these are O.D. measurements)

for a tuning of around 30 hz you'r looking at a port around 4"W x 12.5"H x 32"Length...

eh it's late i could have my number wrong but i think that's about right

[appleyard 0]

thanks man

Actually I used these programs

http://www.subwoofertools.com/forum/ported-box.asp

which I found it not flexible enough. If you try to key in 34 X 18 X 22.75 @ 30hz you will have crazy port dimension.

Just wondering what program do you use there. I have tried tons of programs but all of them gives me different result.

thanks

Wynold

[appleyard 0]

How about this

Outside dimension

33 wide

17 tall

20 deep

with port dimension at 30hz

3.5 wide

15.5 tall

32.75 long

Does it sounds right?

Edited May 29, 2007 by appleyard

[Joeys91 0]

i have a 15" Q in a 4cu feet ported box tuned at 30 Hz and this this KNOCKS it broke my rear view mirror! and all my windows flex